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排序方式: 共有290条查询结果,搜索用时 31 毫秒
1.
《Comptes Rendus Chimie》2015,18(2):215-222
A series of chiral tridentate Schiff-base ligands and their polymer-supported ligands were conveniently prepared and introduced as copper(II) chiral complexes for the asymmetric Henry reaction. The structures of these ligands have been characterized by IR, 1H NMR, 13C NMR and MS. The experimental results showed that the corresponding β-nitro alcohols were obtained in moderate to high yields (up to 98%) with up to 98% ee under mild conditions. The complex catalyst forming from copper(II) polymer-supported ligands could be recycled by a simple filtration and reused 6 times at least with similar good catalytic effect (about 94% yield and 90% ee). 相似文献
2.
《Arabian Journal of Chemistry》2022,15(7):103914
A magnetically separable palladium nanocatalyst has been synthesized through the immobilization of palladium onto 3-aminopropylphenanthroline Schiff based functionalized silica coated superparamagnetic Fe3O4 nanoparticles. The nanocatalyst (Fe3O4@SiNSB-Pd) was fully characterized using several spectroscopic techniques, such as FT-IR, HR-SEM, TEM, XRD, ICP, and XPS. The microscopic image of Fe3O4 showed spherical shape morphology and had an average size of 150 nm. The Pd-nanoparticles exhibited an average size 3.5 ± 0.6 nm. The successful functionalization of Fe3O4@SiNSB-Pd was identified by FT-IR spectroscopy and the appearance of palladium species in Fe3O4@SiNSB-Pd was confirmed by XRD analysis. While XPS has been utilized for the determination of the chemical oxidation state of palladium species in Fe3O4@SiNSB-Pd. Several activated and deactivated arene halides and olefines were employed for Mizoroki-Heck cross-coupling reactions in the presence of Fe3O4@SiNSB-Pd, each of which produced the respective cross-coupling products with excellent yields. The Fe3O4@SiNSB-Pd shows good reactivity and reusability for up to seven consecutive cycles. 相似文献
3.
Abstract An advanced process for manufacturing polyacetal resin has been developed. First, a new technology for the production of highly concentrated aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mol water per mole formaldehyde, methylal oxidation produces only 1 mol water for every 3 mol formaldehyde. Thus, the output from methylal oxidation is more than 70% formaldehyde, compared with 55% from methanol oxidation. Second, a new extraction distillation process for formaldehyde purification was developed in order to get highly purified formaldehyde directly from formalin. By using highly purified formaldehyde, an end-capped polymer was obtained in the presence of acetic anhydride as a chain transfer or end-capping agent during polymerization. Third, the relatively high formaldehyde concentration enhances the formation of trioxane. Purified trioxane is copolymerized with ethylene oxide in the presence of an end-capping agent to get an end-capped polymer with high thermal stability. Two new intermediates from the initiation reaction of the copolymerization, 1,3,5,7-tetraoxacyclononane (TOCN) and 1,3,5,7,10-pentaoxacyclododecane (POCD), were isolated, and a new initiation mechanism was proposed. Fourth, the world's first acetal block copolymer was commercialized by the polymerization of formaldehyde in the presence of a lubricant functional polymer having an active hydrogen atom. This acetal block copolymer exhibits super lubrication properties. 相似文献
4.
高产率合成了一种新的Schiff-base结构化合物,并将其表征为高选择性聚合物膜汞离子选择性电极载体。考察了不同增塑剂及离子交换剂对膜电极响应性能的影响,在最佳膜组分条件下测得该电极对汞离子的线性响应范围为1.0×10-6~3.0×10-4mol/L,响应斜率为(29.3±0.3)mV/dec,检出限为2.6×10-7mol/L;该电极响应速率快(小于12 s),可在较宽的pH范围内(pH2.8~5.6)使用,且其它常见碱金属、碱土金属以及过渡金属离子对该测试电极的干扰小;可准确检测自来水中汞离子的浓度。 相似文献
5.
Yingying Wang Zhuangdong Yuan Yunjie Guo Xuxiao Ma Zitong Meng Jingquan Sha Haifeng Zhang 《无机化学与普通化学杂志》2020,646(20):1696-1701
Two dinuclear LnIII-based clusters, namely [Dy2L2(NO3)2(DME)4] ( 1 ) and [Gd2L2(NO3)2(DME)4] ( 2 ) [H2L = (E)-2-((2-hydroxybenzylidene)amino)phenol] were obtained under hydrothermal condition. Two LnIII ions are bridged by two phenolic hydroxyl oxygen atoms, and the distances of them are 3.829 Å (Dy1–Dy1A) and 3.860 Å (Gd1–Gd1A). Two Dy1–O–Dy1A and Gd1–O–Gd1A angles are 109.4° and 109.8°, respectively. Magnetic studies reveal a weak antiferromagnetic interaction between Gd ions in complex 2 , and single-molecule magnet behavior for 1 with Ueff = 49.9 K and τ0 = 1.54 × 10–6 s. 相似文献
6.
Pariya Bazyari Masoumeh Tabatabaee Navid Nasirizadeh Michal Dušek Václav Eigner 《无机化学与普通化学杂志》2020,646(17):1444-1448
Reaction of 4-amino-5-methyl-1,2,4-triazol-3(2H)-thione (AMTT) and 4-amino-6-methyl-3-thio-3,4-dihydro-1,2,4-triazin-5(2H)-one (AMTTO) with 2-hydroxybenzaldehyde led to the synthesis of corresponding Schiff base ligands [(Z)-4-((2-hydroxybenzylidene)amino)-3-methyl-1H-1,2,4-triazole-5(4H)-thione ( L1 ) and (Z)-4-((2-hydroxybenzylidene)amino)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one ( L2 )]. Treatment of synthesized Schiff base ligands with CuCl provided the complexes [Cu(L1)3Cl] ( 1 ) and [Cu(L2)2Cl] ( 2 ). Synthesized complexes were characterized by elemental analyses, IR spectroscopy and X-ray diffraction studies. Complex 1 consists of a metal ion coordinated with one chloride ion and three Schiff base ligands via sulfur atoms in a distorted tetrahedral environment, whereas 2 consists of a metal ion coordinated with one chloride ion and two sulfur atoms from two different Schiff base ligands in a trigonal planar arrangement. Crystal data for 1 at –153 °C revealed an orthorhombic space group Fdd2, a = 34.8088(7), b = 33.8156(8), c = 11.6142(2) Å, Z = 16, R1 = 0.0357; for 2 at –178 °C the symmetry was triclinic, space group P1 , a = 7.27520(10), b = 15.4620(2), c = 23.7985(4) Å, α = 72.1964(13), β = 86.5208(12), γ = 89.8597(11)°, Z = 4, R1 = 0.0359. 相似文献
7.
Jinyun Zheng Yujian Yu Xiaomin Zhen Erbing Yang Yufen Zhao 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1564-1575
Abstract A series of new nitrogen heterocyclic compounds containing sulfur–ether (8a–8f) and Schiff-base (9a–9q) functionalities were synthesized by the reaction of the pharmaceutical lead compound containing both benzimidazole and 1,2,4-triazole rings. The compounds were characterized by 1H NMR, 13C NMR, FT-IR, HR-MS, and ESI-MS. 相似文献
8.
B. Jarzbek B. Kaczmarczyk D. Sk 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,74(4):949-954
Two series of conjugated aromatic imines (Schiff-base model compounds) with different central groups and various side-group substitutions have been synthesized and characterized by elemental analysis, differential scanning calorimetry (DSC) technique, hydrogen nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR) and ultra-violet and visible light (UV–vis) spectroscopy measurements. The UV–vis absorption of solutions of these compounds in dimethylacetamid (DMA), chloroform and methanol was investigated in the optical range from 240 to 450 nm, where two distinct absorption bands: at 250–280 and 315–360 nm with the different level of absorption have been observed. The influence of compound molecular structure and polarity of solvent on the absorption spectra and the possible optical transitions have been discussed. Structure of diamines in the azomethine models fundamentally affected their spectroscopic properties and conjugation of π-electrons. 相似文献
9.
10.
Vitalina M. Nikitina Oksana V. Nesterova Vladimir N. Kokozay Viktoriya V. Dyakonenko Oleg V. Shishkin Julia Jezierska 《Polyhedron》2009
Four new heterometallic Cu(II)/Cr(III) complexes with N,N-dimethylethylenediamine (dmen) and its novel Schiff-base derivatives, N′-[(1Z)-3-amino-1,3-dimethylbutylidene]-N,N-dimethylethane-1,2-diamine (dmenac) and N′-((1Z)-3-{[2-(dimethylamino)ethyl]amino}-1,3-dimethylbutylidene)-N,N-dimethylethane-1,2-diamine (dmen2ac), have been easily prepared by self-assembly and characterized by spectroscopic methods and single crystal X-ray analysis. The structures of all the complexes are assisted by numerous hydrogen bonds that provide a web of interactions and mould the supramolecular architectures of the compounds. Variable-temperature (1.8–300 K) magnetic susceptibility measurements reveal Curie-Weiss paramagnetic behavior of all the compounds, supported by EPR studies. 相似文献